a) Field of the Invention
The present invention relates to aircraft landing gear, and more particularly to such a landing gear which is particularly adapted to be used with larger aircraft and provide proper ground clearance and also clearance for inspection and maintenance of the landing gear.
b) Background Art
Airplanes commonly have retractable landing gear, where the landing gear has a stowed position within the airplane structure, and an operating position where the landing gear extends from the airplane structure so that the landing gear wheels can properly engage the ground surface. Accordingly, the fuselage of the airplane (or other body carrying the landing gear) is provided with landing gear well doors which remain closed during flight, but are opened before landing to permit the landing gear to be moved to its operating position for ground engagement upon landing of the airplane.
Proper utilization of space is, of course, very important for most all aircraft. Also, it is necessary to provide the various components of the airplane with proper access and clearance for maintenance, repair, etc. With landing gear, for example, it is desirable that when the airplane is on the ground, the landing gear doors and other components are positioned to provide proper clearance to facilitate wheel inspection and maintenance. Also there are minimum clearance requirements on both sides of the body to accommodate wheel change and supporting equipment.
A search of the patent literature has disclosed a number of devices related generally to aircraft or other transportation vehicles, showing various doors and other closure mechanisms for a variety of purposes. These are the following:
U.S. Pat. No. 2,378,856 (Laddon et al.) illustrates a xe2x80x9csliding closure for aircraftxe2x80x9d. In FIG. 1, there are shown the closure doors 24 which are flexible and move in tracks from a lower position (on the left side of FIG. 1) to an upper position (right side of FIG. 1). This could be used, for example, for providing a bottom opening for the discharge of bombs. FIG. 4 shows another embodiment where this could be used as a sliding enclosure for a tail gun compartment or xe2x80x9cany other access openingxe2x80x9d.
U.S. Pat. No. 2,445,131 shows a door mounting system for an aircraft where the door moves a short distance laterally in the channels 13-16. When the door is moved to the position in FIG. 3, the several rollers 26 become aligned with an upper channel 35 and the lower channel 36 and then the doors slip laterally to the position of the FIG. 5 to its open position.
U.S. Pat. No. 2,604,281 (McCall et al.) discloses a door structure for a bomb bays in the military aircraft. In FIG. 3, there is shown a linkage by which the two bomb bay doors 7 are moved outwardly to the open position. As can be seen in FIG. 3, the left door 7 pivots about the location 53, and is interconnected to the location 53 by a strut 65. A rod 69 is actuated by the hydraulic actuator 50 to move the arm 66 downwardly to in turn cause the strut 67 to push the door 7 upwardly and outwardly, rotating about the pivot point 73. The right door 70 is connected to an arm 55, the lower end of which connects to the right door 7 and the upper end of which connects at 77 to an actuating linkage connected to the hydraulic actuator 50. When the hydraulic actuator 50 is extended, this moves the upper end of the arm 55 on an arcuate path counterclockwise to open the right door 7.
U.S. Pat. No. 2,658792 (Scott) illustrates a door which is slid from a closed position parallel to the outside contour of the body to a forward position so that it is within the body of the vehicle.
U.S. Pat. No. 2,670,156 (Clark et al.) shows a catapult hook mechanism and FIG. 9 shows the door and the hinge mechanism by which the door 81 is moved. There are two L-shaped strips 86 and 87 pivotally connected at a center location, one being pivotally connected at 90 structure, and the other end at 95 to the door panel. The second member is mounted at 94 at a slot and has a pivot connection 92.
U.S. Pat. No. 2,921,501 (Parot) relates to a system for an aircraft to release a load, such as bombs. FIG. 5 shows a mechanism for opening the two lower doors 2. There is provided a pair of arms which are actuated by the member 7. Each of the doors has two rollers which fit in respective curved tracks 29 and 30 to move the doors out of their closed position, then rotate these upwardly to the position within the fuselage, such as shown in the broken lines at the left of part of FIG. 5.
U.S. Pat. No. 3,174,712 discloses a hold door for an aircraft. This is designed so that the door can have a circular cross sectional configuration to conform to the contour of the fuselage. The door member 6 and 7 are mounted in sideways so that these can move from the closed position in a circular path upwardly along the outside of the fuselage.
U.S. Pat. No. 2,486,721 (Miczinski) shows a closure flap assembly for a lift drive mechanism in an aircraft. There are two flaps I and 6. The forward flap is pivotally located at a forward location and is rotated about that pivot location by a link 4 which rotates counterclockwise (see FIGS. 1-3) to move the door from the closed position (FIG. 1) to the open position (FIG. 3). The swing end of the link 4 is connected by the link 5 to a member 14 which connects to the rear flap 6. Movement of the link 5 causes the flap 6 to move linearly in a slot 10, and it is also connected by a link 12 to cause a rotating motion of the flap 6 so that it is located in its open position (FIG. 3) to extend downwardly.
U.S. Pat. No. 3,506,223 (Flemming) discloses an airplane having a lifting drive with two flaps which are moved from a closed position (FIG. 1) through an intermediate position (FIG. 2) into an open position (FIG. 3). The member 5 is attached pivotally to two arms 6 and 7 positioned and configured so that the flap 5 swings downwardly and rotates. The forward flap 4 is fixedly connected by the member 12 to a pivot location. The member 12 and the link 6 are interconnected by a link 13, and are driven by a linear actuator.
U.S. Pat. No. 3,585,757 (Ritchie et al.) discloses a passenger door for an aircraft which is adapted for use in high altitude flights where the cabin is pressurized. To open the door, the door is moved inwardly and upwardly and travels on tracks that have a non-constant curvature and extend upwardly.
U.S. Pat. No. 3,718,171 (Goodwin) shows a door for an aircraft, and more particularly for the cargo hold of the aircraft, where the door is made in two sections pivotally connected to one another. The door is hinge mounted at its upper end, and there are intermediate jacks 26 at the location of the hinge connection for the two door sections to provide limited movement of the two door sections relative to one another when the door moves to its open position.
U.S. Pat. No. 2,457,625 (Amiot) discloses a means for controlling the closing and opening of two lower doors P. The two doors are moved from the closed position (FIG. 1) to an intermediate position where the outer edges of the door are lifted upwardly by the arms 7 moving vertically, and then the arms 7 move circularly about center axis 11 to rotate the doors to the stowed position of FIG. 3 within the fuselage.
U.S. Pat. No. 2,731,221 relates to an aircraft door installation for high speed aircraft, particularly the type from which bombs or other loads are dropped in flight. There are right and left door sections, with each section comprising two door panels pivotally mounted to one another at 14. The outer door section is hinge mounted to the aircraft structure at its upper outer pivot location 13. An arm 15 extends upwardly to a pivot location, and the lower end is pivotally mounted to the inner door. As each door section is moved outwardly and upwardly, the two panels of each section rotate toward one another and in the fully open position the outer door is above the inner door, and both extend laterally outward from the aircraft.
U.S. Pat. No. 5,181,677 (Kaplin et al.) discloses a door assembly for an aircraft where there is a sliding door secured by tracks and is moved laterally between its open and closed position.
It is an object of the present invention to provide an improved landing gear door assemblies having a desirable balance of operating features, and which are particularly adapted to provide proper clearance for the landing gear, maintenance, and tire replacement and repair, while yet maintaining proper effective operation to meet the overall requirements of the aircraft.
The door assembly of the present invention is arranged to be used in conjunction with the landing gear of an airplane, where the landing gear has a stowed position in the airplane and an operating position. The airplane has a landing gear door opening which is defined at least in part by first and second door opening edge structures, through which the landing gear travels on a travel path moving between its stowed an operating positions.
In a first and second embodiment, the door assembly comprises first a panel section comprising at least first and second panels, each of which has first and second side edges and an alignment plane extending between the first and second side edges. The panels have a closed position where the panels are positioned side by side to extend across at least a portion of the door opening.
There is also a positioning section operatively connected to the panel section to move the panels from the closed position to an open position where the panels are in proximity with one another, with the alignment planes at least partially overlapping one another and the panels being clear of the traveling path of the landing gear.
This first and second panel each have an outside surface which in the closed position is facing ambient atmosphere, and an inside surface. The positioning section is arranged so that the first and second panels are moved to the open position where the inside surface of one of the panels is adjacent to the outside surface of the other of the panels.
In a preferred form, each of the first and second panels is fixedly attached to first and second mounting arms, respectively, and a second end connected to its related panel. Each panel moves from its closed position to its open position by traveling rotatably about the fixed pivot location of its related mounting arm.
In a preferred form, the panels and there related mounting arms are arranged to rotate in a direction away from the second edge structure and toward the first edge structure, and each mounting arm in the closed position of the panels extends from its related panel in a direction away from the second edge structure to its related pivot location which is spaced from its related panel away from the second edge structure.
More specifically, when the panels rotate from the closed position to an intermediate position, the two panels are positioned below their related pivot locations, and when the panels are moved to the open position, the panels are further from the second edge structure than their related pivot locations. Also in a preferred configuration, the first and second arms are connected by a connecting link having a first link pivot connecting end connected to the first mounting arm at a location spaced from its related arm pivot location, and a second link pivot connecting end connected to the second arm at a location spaced from its related arm pivot location. Also, the first and second ends of the connecting link are positioned from their related arm pivot locations by approximately equal distances. Further, the arm pivot locations are spaced at a distance approximately equal to spacing of the link pivot locations. In this manner, the first and second pivot locations and the first and second connecting locations of the link form a parallel linkage.
In this first embodiment, there is a third panel having an alignment plane and first and second side edges. The first, second and third panels are positioned, in the stowed position, so that the three panels extend across the door opening. The positioning section is arranged to move the third panel to a location having its alignment plane overlapping with an alignment plane of at least one of said first and second panels.
In a preferred form, the third panel comprises a rigid panel component having first and second edge portions. The first edge portion has a pivot connection to said first edge structure and pivots about the pivot connection of the first edge structure between the open and closed positions.
There are operative linkage connections between the first, second and third panels, and there is an actuator connected to at least on of said panels to cause rotation of the connected panel and thus cause rotation of the other two panels. In this specific embodiment, the actuator is connected to the third panel.
In this first arrangement in the airplane, the door assembly described above is positioned at a side location of a fuselage of the airplane, and the third panel section is positioned at a furthest outward position from the center of the fuselage, relative to the first and second panels. The three panels are arranged so that in the closed position, these extend from the side portion of the airplane toward the center, and in the open position, they are positioned at the side of the airplane and extend laterally outwardly from the side of the airplane.
In the third embodiment, the first and second panels, having outside surfaces and inside surfaces, are arranged relative to the positioning section so that in moving the panels from the closed position to the open position, the inside surfaces of the two panels are in the open position facing one another, and the alignment planes of the two panels are at least partially overlapping.
More specifically these panels of the second embodiment are hinge connected along adjacent side edges, and in the open position, the two panels are rotated toward one another during deployment to the outer position so that the inside surfaces of the two panels face one another.
Desirably, in the third embodiment, the panels are hinge connected along adjacent side edges, and in the open position, the two panels are rotated toward one another during deployment to the open position so that the inside surfaces of the two panels face one another.
The positioning section of this third embodiment comprises a main positioning arm which is pivotally mounted about a fixed pivot location. The fist and second panels are operatively connected to the arm so as to be carried rotatably by the arm from the closed position toward the open position. The positioning section further comprises a positioning linkage bound to the arm and interconnected to at least one of the panels so as to cause said one of the panels to rotate relative to the other of said panels.
Also, the positioning section of the second embodiment has a secondary positioning link having one pivot end attached to fixed structure and a having a second end operatively connected to the positioning linkage so that with rotation of the main positioning arm, the secondary positioning arm causes movement of at least one link of the positioning linkage.
In another embodiment, the landing gear door assembly comprises first and second panel sections, each of which comprises at least first and second panels. Each of these first and second panels has first and second side edges and an alignment plane extending between the first and second side edges. The panels have a closed position where the panels of the two panel sections are positioned in side by side alignment and cross the door opening.
The present invention further comprises a landing gear door apparatus where there are first and second landing gear door assemblies. First door assembly comprises a first panel section comprising at least first and second panels. The panels have a closed position where the panels are positioned side by side to extend across at least a portion of the door opening region. There is a first positioning section operatively connected to the first and second panels to move said panels from a closed position to an upper open position where the first and second panels are in proximity with one another. There is a second landing gear assembly which comprises a second panel section having third and fourth panels. The third and fourth panels have a closed position where the panels extend across at least a portion of the door opening region.
There is a second positioning section operatively connected to the second section to move the panels from the closed position to a lower open position where the third and fourth panels are in proximity with one another, and positioned below said first and second panels in their open position.
In the method of the present invention, there is provided a door closing assembly as described above, comprising at least the first and second panels. Initially, the panels are positioned in a closed position where they are in side by side relationship across at least a portion of the door opening. Then a positioning section is utilized to move the panels from the closed position to the open position so as to be in proximity to one another, with the alignment planes at least partially overlapping one another. Further, the panels are clear of the traveling path of the landing gear.
Other features of the present invention will become apparent from the following detailed description.